FR2643891A1 - DEVICE FOR FILLING PETRI BOXES - Google Patents

Abstract

This device is equipped with a rotary transfer plate 1 capable of conveying the boxes in the open state from a dispensing station for empty boxes to a filling station, then from the latter to a receiving station for filled boxes; this plate comprises an upper plate 10 whose openings retain the lids of the boxes and a lower plate 11 whose openings are crossed by the box bottoms, these funds constantly being supported on a refrigerated fixed sole 55 during their transfer; the turntable 1 is driven by means of a motor disk 6 placed under the sole 55, by means of a magnetic coupling comprising a series of magnets 71-12 placed opposite each other. Laboratory equipment.

Description

t

  DEVICE FOR FILLING PETRI BOXES

  The present invention relates to a device for filling petri dishes. Petri dishes are small boxes of

  circular contour, made of transparent plastic, which contains

  a nutrient product such as a mixture of agar and distilled water; they serve as a development medium for cultures containing micro-organisms and are used in large numbers by the laboratories of analysis especially in the research

medical and industry.

  The agar / distilled water mixture is at ordinary temperature in solid form, having the consistency of a gelatin. Before being introduced into the boxes at a temperature of the order of 42 to 50 ° C., the mixture is brought to a temperature of

  of the order of 100 C to take a liquid form; it is distributed

  in the boxes to form a regular layer,

  flat surface. The box can be used only after hardening

  of the product, the curing time being of the order of

  ten minutes at room temperature.

  It has already been proposed devices intended to perform

  automatic filling of the boxes.

  Thus, in document FR-A-2 433 752, a device is described

  fillers in which the boxes to be filled are

  one after the other by means of a rotating horizontal plate, at a filling station which has an agar dispensing nozzle. The boxes are presented at the agar dispensing station in the open state, that is to say the lid kept spread over the bottom, one after the other. This is possible thanks to the fact that the rotating transfer plate is composed of two circular horizontal coaxial and superimposed plates, which are each pierced with circular openings regularly distributed at their periphery and in correspondence with each other; the openings of the upper plate have a diameter slightly smaller than that of the lids but slightly larger than that of the bottoms of boxes, so

  that they allow the passage of the latter by retaining only

  lids; on the contrary, the lower plate is provided with openings shaped to receive and support the

funds during their transfer.

  The agar dispensing nozzle extends between the two plates, which makes it possible to supply the

  boxes appearing in turn at the filling station.

  This known device is equipped with a single carousel which acts both as a station for dispensing empty boxes and as a receiving station for full boxes; the carousel contains several piles of boxes which are distributed at its periphery forming columns, the latter being retained by vertical rods. This known device gives satisfaction generally

  but has some disadvantages, however.

  In the first place, the box capacity of the device, and hence its autonomy, are limited because of the use of a single carousel; an increase in the number of columns per carousel would pose difficulties related to weight

and the clutter of it.

  Secondly, the system for transferring the boxes from the carousel to the transfer tray, and conversely from it to the carousel (after filling) is relatively complicated and subject to breakdowns because it requires the use of mobile means which ensure the holding of the penultimate box of the column during the sampling or the introduction of the last one, that is to say of the lowest box; the complexity of this system requires

  moreover, to work at a relatively low pace.

  Third, if, as is relatively common, there are defects in the filling process, these defects may lead to splashing or spills of the product next to the boxes, there is a problem related to the difficulty of cleaning the device; indeed the cleaning requires many disassembly, including that of the tray, and causes a relatively long immobilization of the device,

  immobilization during which production is stopped.

  Fourthly, the stacking of the full boxes is done while the product is still liquid, which is a cause of surface unevenness of the agar in the dishes, this due to the inevitable agitation of the product that appears during storage; out, a lack of flatness may pose difficulties especially during subsequent analyzes made by

reading with a camera.

  Finally, it is not possible to collect for immediate use a column of full boxes just stored in the carousel because of the necessary cooling time of the product, as already mentioned above; this can be a disadvantage when the user staff is

  Petri dishes and has a need for urgent use.

  The invention aims to solve these various problems in

  posing a device of the type evoked which is of simple design and of a safe and reliable operation, which works with cadence

  high level, which is easy to maintain especially for cleaning.

  ge, which has a high storage capacity, that is to say that can contain and process without external intervention a very large number of boxes, which allows to obtain agar layers with flat surface, and which produces petri dishes immediately usable (without waiting time). These different results are achieved according to the invention, thanks to the fact that the device which - like the already known device mentioned above - comprises a rotating transfer tray, suitable for

  successively and step by step open boxes (cover

  kept at a distance from the bottom) of a distribution

  buenter empty boxes to a filling station, then the latter to a station receiving filled boxes, this plate being composed of two circular horizontal plates coaxial and superimposed, each pierced by a series of openings

  regularly distributed at their periphery and in corre-

  with the other, the apertures of the upper plate having a diameter slightly smaller than that of the lids but slightly larger than that of the bottoms, so that they allow the passage of the latter retaining

  only the lids, is characterized in that: -

  - On the one hand, the openings of the lower plate have a diameter slightly larger than that of the funds so that they also allow the passage of the latter; - On the other hand, said transfer plate rests, by its lower plate on a flat and horizontal fixed base, so that during their transfer by means of said lower plate, the bottom box is supported on said sole, the driving of the rotating plate being carried out by motor means located under this sole, via

a magnetic coupling.

  Furthermore, according to other interesting features of the invention: - said sole is refrigerated, for example by means of Peltier effect cooling modules; said distributor and receiver stations comprise separate storage means constituted by identical carousels in which the boxes are stacked in columns, the step-by-step rotation of these carousels being in synchronism with that of said transfer tray so that the empty boxes leave one by one the dispensing carousel by escaping successively from the bottom of the neighboring columns while the filled boxes are introduced one by one into the receiving carousel by the base of neighboring columns; the columns of boxes contained in said carousels rest on a horizontal plate covering said transfer plate, this plate being traversed, at each of the dispensing and receiving stations, of an opening which allows the boxes of the dispensing carousel to pass to the plate, and from the latter to the receiver carousel; the means for rotating said carousels

  print to these, for each box, two half-courses succes-

  sives corresponding to half of the angular difference between two neighboring columns; - It is provided with two transfer pistons located one at the dispensing station, and the other at the receiving station and whose diameter is substantially smaller than that of the boxes,

  means - such as rotating cams - being provided to de-

  place these pistons vertically in the axis of the associated opening; said means are used to successively bring the piston in each of the following positions: a) a so-called high position, in which its upper face is substantially flush with said horizontal plate; b) a so-called intermediate position, wherein its upper face is at a lower level than that of said horizontal plate, a height corresponding substantially to that of a box; c) a so-called low position, wherein its upper face is substantially flush with said sole; - The upper face of the piston has a beveled pan and / or a chamfer; the drive of the transfer plate is carried out by means of a horizontal motor disc disposed just below the soleplate, directly above the plate, this disc and the lower plate being each provided with a series of magnets regularly distributed at their periphery opposite each other; - Said bottom plate is supported on the sole by means of antifriction means such as balls and / or ball bearings;

  said filling station comprises an injection nozzle

  a product, such as agar, which is fed by a pump, and is normally positioned horizontally between the two plates of the transfer tray, and that this nozzle is carried by a lever that can be retracted by tilting to clear the access of the sole and allow the removal of said tray; - said bottom plate is indented-outward

  at each opening, so as to enable detection

  the presence of a box bottom in this opening by means of an opto-electronic detector located at the filling station; - it is equipped with a germicidal device comprising a tube of ultraviolet radiation, to which are exposed the boxes

  during their stay at the filling station.

  Other features and advantages of the invention are

  of the description and the annexed drawings which

  a preferred embodiment.

On these drawings:

  FIG. 1 is a diagrammatic top view, with

  partial payments of the scheme; - Figure 2 shows on a larger scale the device of Figure 1 cut by the broken vertical plane 1111; - Figure 3 shows schematically and incompletely in perspective a carroossel storage boxes; FIGS. 4, 5, 6 and 7 are diagrammatic views, in

  vertical section, representing the various stages of sampling

  empty boxes to the filling station; Figures 4a and 5a are schematic top views

  (on a smaller scale) respectively corresponding to

  illustrated in Figures 4 and 5; FIGS. 8 and 9 are diagrammatic views in vertical section illustrating the principle of storing a solid box at the receiving station; - Figure 10 is a schematic side view of the machine, intended to show how the removal of the transfer tray is done, especially for the purpose of cleaning the device. The device shown schematically in top view at

  Figure I has the general shape of a rectangular box recou-

  green by a plate 3 of stainless steel. Inside the box are installed the various control equipment of the device, in particular the drive motors of the moving parts and the electronic components constituting the microprocessor controlling the machine; the latter is connected to a keyboard 1000 which in a known manner allows the operator to respond to requests for instructions from the microprocessor and give him instructions depending on the operation he wants to perform; these instructions aim in particular at the number of boxes to be treated and the volume of agar that must be distributed in each box.

  Reference 102 has been designated as the front face of the

  tif, directed downwards of Figure 1, facing which is turned towards the operator. In the central part of the device, near this front face, is mounted a rotary plate 1. To the rear of the device, symmetrically on each side of the plate 1, are located the empty box dispensing stations and receivers full boxes. The constituent elements of these two stations are identical and have therefore received the same references, the index (a) being attributed to the elements equipping the dispensing station (which is to the right of Figure 1) and the index (b ) to the elements of the receiving station (which is on the left). The nutrient box filling station, such as a mixture of agar and distilled water, located on the front face of the device in the central portion thereof, comprises a nozzle or dispensing cannula 70 which is connected by a flexible conduit 74 has a source 76, in this case a container containing the agar in the liquid state. A suitable pump 75, preferably of the peristaltic type, is adapted to pump the source 76 smoothly (so as not to generate bubbles) successive volumes of agar which are then injected into the boxes by the nozzle 70. The arrow H symbolizes the passage of the agar in the conduit 74. The pump 75 may be one or two channels and adapted to distribute a variable volume, including

  preferably between 3 and 25 ml. The filling rate is advantageous

  about 10 boxes per minute for 15 ml of product.

  The device comprises, in each of the distribution stations

  trice and receiver, a rotating disk-20 driving a carousel containing the boxes. This disc is rotatably mounted about a vertical axis Y and is driven by a suitable electric motor housed under the plate 3, inside the box forming the frame of the device. The discs 20 have centering and driving nipples 21 of the carousels. As seen in Figure 3, each of the carousels is composed of a horizontal lower disk 22 and an upper ring 27; the disc 22 has orifices 23 suitable for being placed on the disc 20 and cooperating with the centering and driving studs 21. This disc comprises a series of peripheral openings 24, angularly distributed regularly; these openings 24 have a diameter slightly greater than that of the boxes. In Figure 3 only an opening 24 has been shown; there are nine openings 24 offset by 40 relative to each other. In the upper ring 27 are provided corresponding openings 26, and the pieces 22, 27

  are connected to each other by means of a series of vertical rods

  shims 25; there are provided four rods 25 per pair of openings 24, 26, these rods for holding a stack of boxes comprising a vertical column housed between these rods. Each column advantageously contains fifty petri dishes, so that the carousel can contain a total of 450 dishes. For each set of four rods 25 provided per column, at least one of these rods, located towards the outside of the carousel, is flexible and its upper end is movable, which facilitates the removal of the column of boxes or boxes. some of the boxes constituting

this column.

  The carousels, after being placed on the discs 20a and b, are driven step by step by the latter in a direction which, when viewed from above, is the opposite direction to that of the hands of a clock, this sense being represented by the arrows F2a and F2b at the

figure 1.

  The transfer plate 1 consists of two circular plates 10, 11 secured to one another by means of a series of spacers 13. They are advantageously made of a high-strength plastic material. The upper plate 10 is pierced by a series of nine openings disposed at its periphery and regularly distributed every 400. Each of these openings has a recess 101 of slightly larger diameter.

  headed up. The lower plate 11 has a slight diameter

  smaller than platinum 10 and also has nine openings

  110, distributed every 40, whose vertical axes coincide with those of the openings 100.

  smaller diameter of the plate 11, the openings 110

  outward through indentations.

  Traditionally, petri dishes are small boxes made of transparent plastic composed of two parts, namely a bottom and a lid. Each of these parts has a side wall of different diameter, the wall of the cover coming to cover that of the bottom when the box is closed; this setting up is practically without friction,

  so that the removal of the lid is effortless.

  According to an important characteristic of the invention, the opening

  Circular ture 100 of the lower plate has a diameter smaller than that of the lid, so that if we move up and down a box in the axis of this opening, the lid remains retained by the edge of the recess 101. By cons , the diameter of the opening 100 is slightly larger than that of the bottom of

  box, so that it can continue to descend through

  opening 100 and releasing the cover; the circular opening 110 as for it also has a very large diameter

  slightly larger than the bottom of the box.

  In the lower face of the plate 11 are housed a series of magnets 12, for example also nine in number regularly angularly distributed every 40. The plate 1 rests by means of a series of balls 14, for example

  three balls arranged at 120, which are advantageously housed -

  in spacers 13, on a fixed horizontal plate 55, which will be called sole. The balls could be advantageously replaced by ball bearings. The plate 55 is made

  in a magnetic material, preferably aluminum alloy

  minium. Reference 5 has been designated a massive plate, constituting

  knock down the frame of the device; it extends a short distance under the sole 55; it carries several guide bearings 50,

  51, 52, vertical axis whose role will be explained later.

  The bearing 52 serves to guide in rotation, by means of appropriate ball bearings, a shaft 60 of vertical axis X. The latter is secured to a disk 6, also of material

  non-magnetic material such as an aluminum alloy, which is disposed horizontally

  taling just below the sole 55; the disc 6 carries a series of magnets 61 identical to the magnets 12 and each arranged in

  correspondence with these. The shaft 60 is rotated

  by a suitable motor not shown, for example by means of a toothed belt 63 meshing with a pinion 62 wedged on the shaft 60. If the plate 1 is placed on the sole 55 so that the axis of the the plate being close to the axis X, by mutual magnetic attraction of the magnets 61 and 12, the plate is positioned exactly in alignment with the disk, so that the magnets 12 and 61 are exactly opposite; thereafter, the rotation of the disc 6 makes, by coupling

  magnetic, the corresponding drive of the plate 1.

  At each of the dispensing and receiving stations, vis-à-vis the trajectory of the carousels 2a and 2b, the upper plate 3 is pierced with an opening 30a, respectively 30b, whose diameter is slightly greater than that of the boxes. During the rotation of the plate 1, after positioning the latter in the X axis, each pair of openings 100, 110 can

  come in correspondence with these two openings 30a, 30b.

  In the bearing 50 of the frame plate 5 are guided in translation of vertical axis two pistons 4a, 4b in alignment with

  the openings 30a, respectively 30b. In Figure 2 is shown

  felt the piston 4b of the receiving station. An identical piston

  is located at the vending station.

  The pistons 4 have an upper face 48 with chamfered edge 401 and having an inclined face 400 which, as will be seen below, facilitates the passage of the bottom of the boxes on the

face 48.

  The piston head 4 is carried by a rod 40 whose end

  lower half is provided with a rolling roller 41 which bears against an annular cam path 44; this cam path is fixed on a disc 42, which is wedged on a vertical shaft 43 guided in rotation in ball bearings housed in the bore 51. A suitable electric geared motor (not shown)

  drives the cam 42 in rotation, via a belt

  notched belt 46 which meshes with a pinion 45 integral with the shaft 43. The rotation of the cam 42 causes the vertical displacement of the piston. As will be seen later, the profile of the cam is

  determined to give the piston three positions

  durability, a low position, a high position and a

intermediate position.

  On the side of the front face of the device, the frame plate 5 is recessed so as to form a box 53 extending under part of the trajectory of the boxes when transported by the turntable 1. In this box 53 is a refrigerating device 8. The latter consists of a Peltier cooling module 8, suitably supplied with

  electrical energy by means not shown in the figures.

  We know that a Peltier effect cell behaves like a heat pump, without moving parts. It is composed of a cold face where thermal energy is absorbed by electrons passing from one semiconductor to another; the current source provides the energy required to pass the electrons through the system; the hot face releases the energy to the ambient air through a heat exchanger. The cold face 80 of the module 8 is glued directly under the soleplate 55, while the hot face 81, directed downwards, carries fins 82 of dissipation of heat. A ventilation system comprising one or more fans 83 makes it possible to pass a flow of air

  at room temperature in box 53 to eliminate heat

  dissipated by these fins 82. Module 8 thus achieves a

  constant cooling of the sole 55.

  It can be provided several modules 8, preferably connected in series, and arranged in an arc so as to cover at least part of the trajectory of the boxes, when

  these circulate in the device by means of the turntable

  1. The agar dispensing nozzle 70 is disposed horizontally

  and extends between the two plates 10 and 11, so that its outlet coincides substantially with the center of the openings 100, 110. The nozzle 70 is removably fitted in a groove provided in the upper end of a lever 7 which is articulated on the frame of the device about a horizontal axis 73. This lever 7 is normally held in the vertical position by means of a magnet 54 carried by the frame, cooperating with another magnet 71 secured to the lever. The lever 7 can therefore easily be tilted forwards by pivoting about the axis 73, which makes it possible to disengage the front face of the device in order, in particular, to remove the plate 1 with a view to

  cleaning, as will be seen later.

  Above the filling station, where the nozzle is located, there is provided a protective cover 32, preferably made of transparent plastic, hinged to a support 31 integral with the

  upper plate 3. Under the hood 32 is fixed a German device

  micide constituted by a lamp 33 emitting ultraviolet radiation

  purple; this radiation, represented by arrows r, is directed towards the boxes passing to the agar feed station, and has the role of destroying microbial germs and other micro-organisms

  can be in the boxes so as to ensure

  production of cans filled with a perfectly sterile agar.

  Note also that there is provided at the filling station a detector shown schematically in Figure 2 under the reference 72; it is a detector of known type, for example opto-electronic transmitter cells and receiving a

  electromagnetic radiation, directed towards the notch correspon-

  at openings 110 formed in the lower plate. In the absence of a bottom of box in the opening, the radiation is not reflected, which indicates the absence of a bottom, and a

  indicative signal of this anomaly is then provided to the micropro-

  cessor. The device is used as follows: A carousel containing the number of petri dishes that is to be filled is placed in the box dispensing station, the bottom disk 22 of the carousel being placed on the drive disk 20a. The boxes to be treated are arranged regularly in each of the columns defined by the vertical rods 25, so that all these columns contain the same number of boxes, to a close box (if the total is not divisible by 9). At the receiving station is set up a

  another carousel that is empty of any box.

  The operator, using the keyboard 1000, gives the microproces-

  instructions on the operation to be carried out, indicating in particular the number of boxes to be treated and the volume of agar that must be distributed per box. At the beginning of the operation, the drive disc 6 is briefly rotated so as to achieve a perfect centering of the transfer tray 1 in the X axis, in the case where the initial centering would not have been done properly. automatic way, and in order to make up for any small games. The cams 44 are in a position such that the piston 4a is in the high position, that is to say that its upper face 48 is flush with the upper face of the plate 3; conversely the piston 4b is in the low position, so that its upper face

  48 is flush with the sole 55 (position of Figure 2). Appropriate detectors are provided to control initially and also

  throughout the operation, the correct positioning

  carousels and transfer tray.

  The transfer of an empty box and its delivery to the feed station will now be described with reference to Figures 4 to 7. The carousel 2a is rotated so that one of its exhaust openings boxes 24 arrives vis-à-vis the opening 30a; the piston 4a is in the up position (Figure 4). The supply movement of the column of empty boxes is shown by the arrow f in Figure 4. The inclined portion 400a promotes the gradual passage of the lower face of the bottom plate of the plate 3 of the piston 4a. The cam 42a is then rotated to cause the piston 4a to descend to an intermediate position in which the face 48 is recessed downwards by a height corresponding to that of a box; this downward movement on a limited stroke is shown by the arrow g in Figure 5. The lower box of the stack, referenced 9 ', is thus extracted from the carousel. Then, the carousel 2a is rotated on an angular stroke of 200, so that the stack of remaining boxes is astride, by the lower box 9 ", on the plate 3 and on the opening 30a (see FIG. 5a, where this rotational movement of the

  carousel was represented by the arrow h).

  Continued rotation of the cam 42 then causes the

  complete descent of the piston 4a, which reaches a low position o its upper face 48 is in the same plane as the upper face of the sole 55. During this downward movement shown by the arrow i in Figure 6, the cover 91 'of the box 9' is retained by the upper plate 10 while the bottom 90 'box is housed in the opening 110 of the lower plate 11. The drive disc 6 is then driven on an angle of 40 in order to conveying the box 9 ', in the open position, to the filling station. This rotation is shown by the arrow F1 in Figure 1; it is clockwise, that is to say in the opposite direction to that of the carousels. A pair of openings 100, 110 then comes to position itself under the opening 30a, and the operation can begin again for the removal of the last box of the stack corresponding to the next column in the carousel 2a; for this purpose

  last is turned from an angle of 20 always in the same direction.

  The picked boxes therefore arrive successively at the filling station, this movement being represented by the arrow j at the

figure 7.

  During this movement, according to an important feature of the invention, the can bottoms 90 are supported on the

  sole 55, that is to say on a refrigerated plane. This refrigeration

  boxes, before and after filling, will favor the

  cooling of the agar and thus accelerate the hardening.

  When a box to be filled has arrived at the nozzle, the microprocessor controls the start of operation of the pump 75, which sends a dose of agar to the nozzle.

  determined 95, which is injected into the bottom of box 90.

  After filling, still transported by the turntable 1, the boxes arrive successively in the open state above the piston 4b, which is in its lower position (face 48 flush with the sole 55. At this stage, due to of the role

  refrigeration of the support plate 55, the agar was

  solidified. The cam 42b will then cause the storage of the solid box inside the carousel receiver 2b, this by

  a similar procedure but reversed with respect to the opera-

  sampling of empty boxes. For this, the rotating cam

  42 first of all carries out the raising of the piston 4b at an international level.

  median corresponding to a withdrawal of a height of a half-box relative to the plate 3. During this lifting, the piston 4 brings the bottom 90 inside the cover 91 and therefore performs the automatic closing of the box. The piston being in its intermediate position, the carousel receiver 2b is rotated so as to bring a column of full boxes in support of the box which is waiting; the piston 4b is then completely raised and is introduced into the bottom of the can stack by raising all the other boxes; the carousel 2b is then rotated by 20 so as to bring the whole of the pile astride between the opening 30b and the bearing surface formed

  by the plate 3, waiting for the next box.

  It should be noted that the bottoms of boxes often have a certain concavity, delimited by a protruding rim 900; during the passage of the column of full boxes of the piston on the plate 3, the inclined portion 400b prevents this rim 900 from catching against the piston (see Figure 9) which would have the effect of tilting the box, which would then to hang on

the edge of the opening 30b.

  In FIGS. 8 and 9, the movements of lifting the piston and moving the column of full boxes have been shown

  respectively by the arrows k and 1.

  In FIG. 7, the arrows R represent the flow of cooling air to the fins of the cooling system 8 with Peltier effect. Figure 10 shows how it is very easy to remove the tray 1 in particular for cleaning the tray and the support plate 55 in the case of the agar has spilled unexpectedly into the device. For this, the cover 32 is first raised (arrow n); the nozzle 70 having been removed, the lever 7 is tilted downwards (arrow m), which releases the front face 102 of the device. By exerting on the plate 1 a horizontal force p towards the front, sufficient to overcome the magnetic attraction forces of the coupling 61-12, it provokes the

  removal and extraction of the tray 1. During this trip,

  14, the balls 14 roll on the sole 55, which further facilitates the operation. After cleaning just make the

  same movements in the opposite direction and the plateau is automatically

  in a good position. The microprocessor is programmed in such a way that when the detector 72 detects the absence of a bottom of boxes the

  microprocessor does not control the start of pump 75.

  This occurs in particular when a box has been placed upside down in the carousel 2a; indeed, the entire box is then retained by the upper plate 10. Because the pump is not put into operation, it does not occur

  no inadvertent agar distribution, and the operation continues

  normally bare, without interruption for the other boots. The box placed upside down is stored normally, always at

  upside down, with the boots full in the carousel receiver 4b.

  As an indication, the forward speeds are chosen so as to obtain a production rate of the order of one box every six seconds. The Peltier effect modules are chosen for use at ambient temperature to bring the temperature of the refrigerated tray to a value of the order of 7 ° C. Under these conditions, the agar is practically hard when the filled box arrives at above the piston 4b, so

  that the movements of the box during its storage do not destroy

  not even the flatness of the agar surface.

  It can be expected to equip the frame of the device with a spirit level to perfectly adjust the horizontality of the sole 55, this to ensure the regularity of thickness

of the product layer.

  Because the stored boots are already cool, it is

  possible to use them immediately.

Claims (13)

  1. Device for filling petri dishes, these boxes   having a circular shape, comprising a bottom on which   te freely a lid of diameter slightly greater than that of the bottom, of the type comprising a rotating transfer tray (1) able to successively and step-by-step open boxes   (9) - cover (91) held apart above the bottom (90) -   from an empty box dispensing station to a filling station, then from the latter to a receiving station filled boxes, this plate (1) being composed of two circular horizontal plates (10, 11) coaxial and superposed pierced   each of a series of circular openings regularly distributed   on their periphery and in correspondence with each other,   the openings (100) of the upper platen (10) having a diameter   slightly smaller than that of the lids (91) but lightly   significantly larger than the funds (90) so that they   the passage of the latter through the retention of the covers, characterized in that - on the one hand, the openings (110) of the lower plate (11) have a diameter slightly larger than that of the bottoms (90) so that they also allow the passage of these; - On the other hand, said transfer plate (1) rests, by its lower plate (11) on a fixed plate (55), flat and horizontal, so that during their transfer by means of said lower plate (11) , the can bottoms (90) are supported on said sole (55), the driving of the plate (1) in rotation being carried out by motor means (63, 62, 6) located under this sole (55), through a magnetic coupling (61, 12).   2. Device according to claim 1, characterized in that said sole is refrigerated, for example by means of modules   Peltier cooling system (8).   3. Device according to one of claims 1 or 2, characterized   characterized in that said distributor and receiver stations comprise separate storage means constituted by identical carousels (2a, 2b) in which the boxes (9) are stacked in columns, the step-by-step rotation of these carousels taking place in synchronism with that of said transfer tray (1) so that the empty boxes leave one by one the dispensing carousel (2a) by escaping successively from the bottom of neighboring columns while the filled boxes are introduced one by one   in the receiving carousel (2b) by the base of neighboring columns.   4. Device according to claim 3, characterized in that the columns of boxes contained in said carousels (2a, 2b) rest on a horizontal plate (3) covering said transfer plate (1), this plate being crossed, to each of dispensing and receiving stations, an opening (30a, b) which allows the passage of boxes of the carousel distributor   (2a) to the plate (1), and the latter to the receiving carousel (2b).   5. Device according to claim 4, characterized in that the drive means in rotation of said carousels (2a, 2b) print to these, for each box, two successive half-races corresponding to half the angular difference between two neighboring columns.   6. Device according to claim 5, characterized in that it is provided with two transfer pistons (4a, 4b) located one at the dispensing station, and the other at the receiving station and whose diameter is substantially greater. smaller than that of the boxes, means - such as rotating cams (42) - being provided for   vertically move these pistons (4a, 4b) in the axis of the opening associated ture (30a, 30b).   7. Device according to claim 6, characterized in that said means (42) can successively bring the piston (4a, 4b) in each of the following positions: a) a so-called high position, in which its upper face (48) is substantially flush with said horizontal plate (3); b) a so-called intermediate position, in which its upper face (48) is at a lower level than that of said horizontal plate (3), a height substantially corresponding to that of a box (9); c) a so-called low position, in which its upper face   (48) is substantially flush with said sole (55).   8. Device according to one of claims 6 or 7, characterized   characterized in that the upper face (48) of the piston (4a, 4b)   has a chamfer (400) and / or a chamfer (401).   9. Device according to one of claims 1 to 8, characterized   characterized in that the drive of the transfer plate (1) is carried out by means of a horizontal motor disk (6) disposed just below the sole (55), directly above the plate (1), this disc (6) and the lower plate (11) being each provided with a series of magnets (61, 12) regularly distributed at their   periphery vis-à-vis each other.   10. Device according to one of claims 1 to 8, characterized   characterized in that said bottom plate (11) is supported on the sole (55) by means of antifriction means such as   balls (14) and / or ball bearings.   11. Device according to one of claims 1 to 10, characterized   characterized in that said filling station comprises a nozzle   injecting (70) product such as agar (95), which is -   powered by a pump, and is normally positioned horizontally   between the two plates (10, 11) of the transfer plate, and that this nozzle (70) is carried by a lever (7) that can be retracted by tilting to clear the access of the sole (55).   and allow the removal of said tray (1).   12. Device according to one of claims 1 to 11, characterized   characterized in that said bottom plate (11) is notched outwardly at each opening (110), so as to allow detection of the presence of a can bottom (90) in this opening by means of an opto-electronic detector   (72) located at the filling station.   13. Device according to one of claims 1 to 12, characterized   characterized in that it is equipped with a germicidal device comprising a tube of ultraviolet radiation (33), to which are exposed the   boxes (9) during their passage at the filling station.